The present invention relates generally to battery strings particularly for use in electric vehicles, and more particularly, to a method and circuit for detecting the position of a battery within a string relative to the other batteries in the string.
In electric vehicles or hybrid electric vehicles, high voltage battery packs or battery strings are used to provide electric power to the powertrain of the vehicle. High voltage battery packs typically comprise a plurality of lower voltage batteries connected in series. At times, the batteries are charged and discharged. Eventually, over extended use, the performance of one or more batteries of the string may degrade. For example, this may be manifested in a failure to hold a charge in a similar manner to the other batteries in the string. Eventually, the particular battery may require servicing.
In order to provide service for a particular battery in the battery string, it is desirable to identify the particular battery subject to degradation. In many current systems, a service technician, through trial and error testing of the individual batteries, is used to identify the degraded battery. This process is time and labor intensive because this often means removal of the battery from the system may be performed.
In U.S. Pat. No. 5,850,351, a distributed management apparatus for a battery pack is described that has battery monitoring modules for each battery. All of the battery monitoring modules are identified by an address. However, this system does not identify the relative position of each individual battery with respect to the others. Identity in the ""351 patent merely identifies the presence of a particular battery module rather than its relative position within the battery pack.
It would therefore be desirable to provide a battery pack control system wherein the relative position of each battery is recorded so that upon the degradation of operation of a particular battery, that battery may be easily removed and replaced from the battery pack.
It is therefore one object of the invention to provide a distributed battery control system that allows the relative location of each battery in the string to be identified.
In one aspect of the invention, a distributed battery control network for a plurality of batteries comprises a plurality of sensing modules. One of each of the plurality of sensing modules is associated with a respective one of said plurality of batteries. Each sensing module has a sequencing input and a sequencing output. A bus interconnects the plurality of sensing modules. A controller is coupled to the bus and communicates with each of the sensing modules via a network.
In a further aspect of the invention, a method for identifying batteries in a distributed battery control network comprises the steps of:
providing a string of a predetermined number of batteries having said predetermined number of sensing modules associated therewith, each battery having a respective sensing module;
determining the relative location of each battery and sensing module within the string; and
assigning a unique address to each sensing module.
One advantage of the invention is that by knowing the location of the battery better control and diagnostics of the battery string may be achieved. Another advantage of the invention is that by knowing a position of a suspect battery, service personnel may easily locate the suspect battery so that it may be quickly replaced. This reduces time and therefore reduces cost in replacing a battery.
Other objects and features of the present invention will become apparent when viewed in light of the detailed description of the preferred embodiment when taken in conjunction with the attached drawings and appended claims.